相关试题
【单选题】
通电线圈产生的磁场方向不但与电流方向有关,而且还与线圈( )有关。 ___
【单选题】
电磁力的大小与导体的有效长度成( )。 ___
【单选题】
组合开关用于电动机可逆控制时,( )允许反向接通。 ___
A. 可在电动机停后就
B. 不必在电动机完全停转后就
C. 必须在电动机完全停转后才
【单选题】
在电力控制系统中,使用最广泛的是( )式交流接触器。 ___
【单选题】
在对可能存在较高跨步电压的接地故障点进行检查时,室内不得接近故障点( )m以内。 ___
【单选题】
接地电阻测量仪主要由手摇发电机、( )、电位器,以及检流计组成。 ___
【单选题】
万用表由表头、( )及转换开关三个主要部分组成。 ___
【单选题】
当一个熔断器保护一只灯时,熔断器应串联在开关( ) ___
【单选题】
线路单相短路是指( )。 ___
A. 电流太大
B. 功率太大
C. 零火线直接接通
【单选题】
螺口灯头的螺纹应与( )相接。 ___
【单选题】
运输液化气,石油等的槽车在行驶时,在槽车底部应采用金属链条或导电橡胶使之与大地接触,其目的是( )。 ___
A. 泄漏槽车行驶中产生的静电荷
B. 中和槽车行驶中产生的静电荷
C. 使槽车与大地等电位
【单选题】
感应电流的方向总是使感应电流的磁场阻碍引起感应电流的磁通的变化,这一定律称为( )。 ___
A. 法拉第定律
B. 特斯拉定律
C. 楞次定律
【单选题】
旋转磁场的旋转方向决定于通入定子绕组中的三相交流电源的相序,只要任意调换电动机( )所接交流电源的相序,旋转磁场既反转。 ___
【单选题】
螺旋式熔断器的电源进线应接在( )。 ___
【单选题】
引起电光性眼炎的主要原因是( )。 ___
【单选题】
按照计数方法,电工仪表主要分为指针式仪表和( )式仪表。 ___
【单选题】
使用剥线钳时应选用比导线直径( )的刃口。 ___
【单选题】
更换熔体时,原则上新熔体与旧熔体的规格要( )。 ___
【单选题】
铁壳开关在作控制电机启动和停止时,要求额定电流要大于或等于( )倍电动机额定电流。 ___
【单选题】
胶壳刀开关在接线时,电源线接在( )。 ___
A. 下端(动触点)
B. 上端(静触点)
C. 两端都可
【单选题】
低压电工作业是指对( )V以下的电气设备进行安装、调试、运行操作等的作业。 ___
【单选题】
绝缘安全用具分为( )安全用具和辅助安全用具。 ___
【单选题】
下列现象中,可判定是接触不良的是( )。 ___
A. 灯泡忽明忽暗
B. 日光灯启动困难
C. 灯泡不亮
【单选题】
熔断器的额定电流( )电动机的起动电流。 ___
【单选题】
降压启动是指启动时降低加在电动机( )绕组上的电压,启动运转后,再使其电压恢复到额定电压正常运行。 ___
【单选题】
特种作业操作证有效期为( )年。 ___
【单选题】
电流继电器使用时其吸引线圈直接或通过电流互感器（ ）在被控电路中。 ___
【单选题】
下列灯具中功率因数最高的是（ ）。___
【单选题】
一般照明场所的线路允许电压损失为额定电压的（ ）。 ___
【单选题】
静电防护的措施比较多，下面常用又行之有效的可消除设备外壳静电的方法是（ ）。 ___
【单选题】
三个阻值相等的电阻串联时的总电阻是并联时总电阻的（ ）倍。 ___
【单选题】
稳压二极管的正常工作状态是（ ）。 ___
A. 截至状态
B. 导通状态
C. 反向击穿状态
【单选题】
（ ）的电机，在通电前，必须先做各绕组的绝缘电阻检查，合格后才可通电。 ___
A. 一直在用，停止没超过一天
B. 不常用，但电机刚停止不超过一天
C. 新装或未用过的
【单选题】
将一根导线均匀拉长为原长的 2 倍，则它的阻值为原阻值的（ ）倍。 ___
推荐试题
【单选题】
- Do you mind if I switch off the radio? ______. Go ahead.
A. Never mind
B. No way
C. No, not at all
D. No, you'd better not
【单选题】
- Could I use your bike for a moment? ___
A. It's well.
B. It doesn't matter.
C. By all means.
D. I have no idea.
【单选题】
-How do you like the story?_______.
A. I'd like to read it
B. I like it very much
C. fine, thank you
D. It's very interesting
【单选题】
- I'll sorry to trouble you.______.
A. Don't say so
B. OK
C. It doesn't matter
D. That's fight
【单选题】
- We ordered 20 boxes of your products, but we have only got 19. - ____
A. You do not have to.
B. It does not matter.
C. We will send another tomorrow.
D. Nothing serious.
【单选题】
--Will you please give the note to him? _________.
A. Certainly, I'll give it to him
B. No, please not
C. Sorry, I don't
D. Yes, please do
【单选题】
- Thank you ever so much for your lovely gift____
A. Never mind
B. I'm glad you like it.
C. Please don't say so.
D. No, It's not so good.
【单选题】
- I'd like to invite you to dinner this Saturday, Mr. Smith.____
A. Oh, no. let's not.
B. I'd rather stay at home.
C. I'm sorry, but I have other plans.
D. Oh, no. That'll be too much trouble.
【单选题】
- Could you please open the window?____
A. I can't.
B. Go ahead.
C. Sure.
D. It's really very kind.
【单选题】
- Do you think I can borrow your bike for a few hours?____
A. I'm afraid you can.
B. I'm sorry, but I really need it this afternoon.
C. Yes, I don't think so.
D. I'll think about it later.
【单选题】
- Thank you very much for the dictionary you sent me.____
A. No thanks.
B. I'm glad you like it.
C. Please don't say so.
D. No, it's not so good.
【单选题】
- How do you like the movie we saw yesterday?____
A. You are welcome.
B. How about you?
C. I've never seen a better movie than it.
D. It is very expensive.
【单选题】
- What do you think of your new teacher____
A. He came to teach us last week.
B. He teaches us English.
C. He has two children.
D. He is very nice.
【单选题】
- Are you going to have a holiday?____
A. Not until next week.
B. Three weeks ago.
C. To Beijing.
D. I'm pleased to hear that.
【单选题】
- You seem to be lost. Need help? ____
A. Yes, would you please help me with the bag?
B. Help me find my key, please.
C. Yes, with pleasure.
D. I'm looking for Zhongshan Road.
【单选题】
- Can you help me clear up the mess____
A. Yes, it doesn't matter.
B. No, that's OK.
C. Yes, help yourself.
D. No problem.
【单选题】
- Does No.20 bus stop at our school?____
A. I go to school by bus.
B. I'm afraid not.
C. You are welcome.
D. I'll not take No.20 bus.
【单选题】
- Can I help you? ____
A. Sorry, I don't need your help.
B. What help can you give us?
C. I'd like to try on these shoes, please.
D. Thanks. You are welcome.
【单选题】
- Sorry to have kept you waiting. ____
A. That's OK.
B. What are you doing?
C. What's wrong with you?
D. Where have you been?
【单选题】
- What is she?____
A. She is a typist.
B. She is talking to her friend.
C. She is having a holiday.
D. She is my sister.
【单选题】
- That's a beautiful cat. I wonder who it belongs to.____
A. It belongs to the
B. rowns. B.The cat is my favourite too.
C. Mind your own business.
D. I can't say anything more.
【单选题】
- Excuse me, could you tell me the time____
A. You'd better buy a watch.
B. It's three thirty by my watch.
C. Can you see the clock?
D. It's late I think.
【单选题】
- What do you think of the movie we saw last night?____
A. The actress is bad.
B. Terrific!
C. The theatre is bad.
D. Nobody was there.
【单选题】
___ No, thanks. I'm just looking around. I'll let you know if I want anything.
A. Could you help me?
B. What will you buy?
C. Can I help you?
D. Do you like to look around?
【单选题】
- Hello, Peter. What do you do?____
A. I am fine.
B. I am not sick.
C. I am a student from Bonn University.
D. I came from Bonn University.
【单选题】
-Excuse me; can I have a seat here?___
A. Be hurry.
B. Come on.
C. Yes, please.
D. Do you mind?
【单选题】
- Shall we sit up here on the grass or down there near the water?___
A. I'd rather stay here if you don't mind.
B. Sorry, I don't like neither.
C. Certainly, why not？
D. Yes, we like these two places.
【单选题】
- What do you do on Sunday?___
A. I 'm a teacher.
B. I play football.
C. You are a student.
D. They clean rooms.
【单选题】
- Our class won the girls' relay race in our school's sports meeting.___
A. That's right.
B. Thanks a lot.
C. Congratulations!
D. It's a pleasure.
【单选题】
- Hi, is Mary there, please?___
A. Hold on. I'll get her.
B. No, she isn't here.
C. Yes, she lives here.
D. Yes, what do you want?
【单选题】
- I am afraid I can't return the book to you before Friday. ___
A. Don't be afraid
B. Be careful
C. Not at all
D. Take your time
【单选题】
- I really don't know how to thank you enough. ___.
A. No problem
B. Think nothing of it
C. Not at all
D. It doesn't matter
【单选题】
- Must I be home before seven? ___.
A. No, you needn't
B. No, you mustn't
C. Yes, you will
D. No, you won't
【单选题】
-I'm sorry to hear that you failed in the exam______.
A. Not at all
B. Oh, thank you.That's very kind of you
C. You are welcome
D. Yes, I'm really sorry
【单选题】
-I will,______.
A. that's all right
B. thank you
C. all right
D. not at all
【单选题】
-Hello, may I speak to Zhao Hua?_____.
A. My name is Zhao Hua
B. I'm Zhao Hua
C. This is Zhao Hua speaking
D. Zhao Hua is me
【单选题】
___This is Mr Smith speaking now.
A. Who are you
B. Who is that
C. Who are you calling
D. What do you want to say
【单选题】
- I was worried about my maths, but Mr. Brown gave me an A.___
A. Don't worry about it.
B. Congratulations! That's a difficult course.
C. Mr. Brown is very good.
D. Good luck to you！
【单选题】
-Would you go to the concert with me?___, but I'm very busy now.
A. I'd like to
B. Sure
C. No problem
D. Certainly
【单选题】
-I'll be away on a business trip. Would you mind looking at my cat?Not at all. _______.
A. I have no time
B. I'd rather not
C. You can leave
D. I'd be happy to
